Pad structures formed in double openings in dielectric layers

摘要

An image sensor device includes a semiconductor substrate having a front side and a backside. A first dielectric layer is on the front side of the semiconductor substrate. A metal pad is in the first dielectric layer. A second dielectric layer is over the first dielectric layer and on the front side of the semiconductor substrate. An opening penetrates through the semiconductor substrate from the backside of the semiconductor substrate, wherein the opening includes a first portion extending to expose a portion of the metal pad and a second portion extending to expose a portion of the second dielectric layer. A metal layer is formed in the first portion and the second portion of the opening.

主权项

1. A method comprising:
performing a first etching on a semiconductor substrate to form a first opening in the semiconductor substrate, wherein a Shallow Trench Isolation (STI) region in the semiconductor substrate is exposed to the first opening; performing a second etching to etch-through the STI region and to form a second opening, wherein the second opening stops on a metal pad; performing a third etching to etch-through the STI region and to form a third opening, wherein the third opening stops on a dielectric material; and forming a conductive feature comprising:
a first portion in contact with the metal pad;a second portion landing on a top surface of the dielectric material; anda third portion connecting the first portion to the second portion.